http://creatingsound.com/2012/08/saving-space-with-linear-audio-in-pro-tools-part-1/

When working on projects with limited audio space, such as apps for mobile, browser-based games or packaged electronics/toys, it is often necessary to squeeze as much out of that space as possible in order to meet or exceed the expectations of the project. From the standpoint of the sound designer, this is likely achieved through compressing the sound files in various ways. However, when working with linear audio that contains gaps of silence or recalls repeated audio, precious space can be saved by editing within your Pro Tools session and exporting the resultant files and session data for programming. While the processes for identifying and editing these two elements are different, their functionality in implementation is essentially the same. In Part 1, I cover the process for getting started, staying organized, and identifying and removing silent gaps.